The answer to 'why is my bathtub overflowing' is that the drain is likely clogged, causing water to back up and overflow the tub. This is a common plumbing issue that can have several causes, such as hair, soap scum, or other debris building up in the drain over time.
Some common symptoms of a clogged bathtub drain include slow draining water, gurgling sounds, or water pooling around the drain. If the tub is overflowing, it's important to act quickly to prevent water damage to your bathroom and surrounding areas.